Histology of somatic embryos and adventitious shoots induced from leaves of Psychotria acuminata

Abstract

Somatic embryos and adventitious shoots were induced from leaves of Psychotria acuminata taken from in vitro plantlets. Leaves were cultured in a Murashige & Skoog (1962) medium, supplemented with 3 mg l^-1 of 6-BAP, 0.01 mg l^-1 of NAA and 2 g l^-1 of phytagel. The highest production of both structures occurred all over the midrib and some sections of secondary ribs of the adaxial surface; their development was not preceded by callus growth. Somatic embryogenesis and organogenesis occurred simultaneously and in a non-synchronized way. Embryos had single as well as multiple cell origin, and in both cases all the developmental stages of somatic embryogenesis formation were observed. On the other hand, the organogenic event was determined by the connection between the vascular tissue of the shoot with the one of the explant. The verification of direct organogenesis and the possibility of developing somatic embryogenic cultures, are key elements in implementing other biotechnology methods to exploit the phytochemical resources of this plant.